Impact of the loss of QuikSCAT on National Hurricane Center operations: Current mitigation efforts and future plans

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1 Impact of the loss of QuikSCAT on National Hurricane Center operations: Current mitigation efforts and future plans Rick Danielson1 and Mike Brennan NOAA/NWS/NCEP National Hurricane Center 1 UCAR visiting scientist Post-QuikSCAT impact on wind warnings in the Gulf of Tehuantepec Recent Gulf of Tehuantepec scatterometer coverage looking for the best winds Examples of hurricane forecast impacts

2 Gulf of Mexico gale / Tehuantepec storm 8-14 January 2010 surface analysis ship/buoy obs ASCAT every 6 h

3 NHC high seas forecast (east Pacific) issued at 9:15 UTC valid at 6:00 UTC wind range maximum (50 kt) October March Tehuantepec gale/storm warning peaks

4 A reference timeseries 32-km NCEP Regional Reanalysis (NARR) NARR domain areal average of the core 30-m wind speed note no QuikSCAT assimilation in NARR (but perhaps in the global driving model?)

5 number of events after QuikSCAT during QuikSCAT Analysis differences (~280 / group) All warnings (35kt +) knots

6 number of events after QuikSCAT during QuikSCAT knots Analysis-Obs differences (~160 / group) Only ship obs > 10kt

7 Ancillary ship data (WMO Pub. 47)

8 Best high winds for Tehuantepec warnings of 2010/2011 For each day of a wind warning, plot ascending then descending satellite winds Boxed in green is the strongest retrieved wind (or satellite with best coverage when two satellites are similar)

9 ASCAT COASTAL ASCAT WINDSAT OSCAT ASCAT High Wind hour (UTC) :40-0:40 TAFB (kt)

10 ASCAT COASTAL ASCAT WINDSAT OSCAT ASCAT High Wind hour (UTC) :30-12:50 TAFB (kt)

11 ASCAT COASTAL ASCAT WINDSAT OSCAT ASCAT High Wind hour (UTC) :40-0:40 TAFB (kt) 50 50

12 ASCAT COASTAL ASCAT WINDSAT OSCAT ASCAT High Wind hour (UTC) :30-12:50 TAFB (kt) 50 50

13 ASCAT COASTAL ASCAT WINDSAT OSCAT ASCAT High Wind hour (UTC) :40-0:40 TAFB (kt)

14 ASCAT COASTAL ASCAT WINDSAT OSCAT ASCAT High Wind hour (UTC) :30-12:50 TAFB (kt)

15 ASCAT COASTAL ASCAT WINDSAT OSCAT ASCAT High Wind hour (UTC) :40-0:40 TAFB (kt)

16 ASCAT COASTAL ASCAT WINDSAT OSCAT ASCAT High Wind hour (UTC) :30-12:50 TAFB (kt)

17 ASCAT COASTAL ASCAT WINDSAT OSCAT ASCAT High Wind hour (UTC) :40-0:40 TAFB (kt)

18 ASCAT COASTAL ASCAT WINDSAT OSCAT ASCAT High Wind hour (UTC) :30-12:50 TAFB (kt)

19 Best high winds for Tehuantepec warnings of 2010/2011 For each day of a wind warning, plot ascending then descending satellite winds Boxed in green is the strongest retrieved wind (or satellite with best coverage when two satellites are similar) ASCAT-coastal (26) ASCAT-high wind (8) WindSAT (15) OSCAT (39)

20 Scatterometer Mentions (%) in NHC Tropical Cyclone Discussions QuikSC AT only QuikSC AT & ASCAT ASCAT only Sharp reduction in percentage of TCDs mentioning scatterometer data in 2010 after the loss of QuikSCAT a decrease of almost half compared to the previous 3-year average Lack of mention mostly due to decrease in coverage with ASCAT leading to fewer passes over TCs and a lack of sampling of the entire TC circulation

21 Hurricane Lisa September 2010

22 Example of ASCAT Use Used as justification to initiate advisories on TD Four-E (later TS Douglas) and set initial intensity TROPICAL DEPRESSION FOUR-E DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP PM PDT TUE JUL ASCAT DATA AT AROUND 16Z SHOWED THAT THE LOW PRESSURE AREA SOUTHWEST OF MANZANILLO MEXICO HAD A BROAD CENTER ELONGATED NORTH-NORTHWEST TO SOUTH-SOUTHEAST. SINCE THAT TIME...SATELLITE IMAGERY INDICATES THAT THE CIRCULATION AND ASSOCIATED SHOWER ACTIVITY HAS SOMEWHAT CONSOLIDATED AT THE SOUTHERN END OF THE ELONGATION. BASED ON THIS...ADVISORIES ARE INITIATED ON TROPICAL DEPRESSION FOUR-E. THE INITIAL INTENSITY IS 30 KT IN AGREEMENT WITH SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB...AS WELL AS THE OBSERVED WINDS IN THE EARLIER ASCAT DATA.... THE ASCAT DATA SHOWED KT WINDS IN A BAND THAT IS CURRENTLY ABOUT 200 N MI FROM THE CENTER IN THE NORTHEASTERN QUADRANT. WHILE THE CENTER OF THE CYCLONE IS EXPECTED TO REMAIN WELL OFFSHORE...

23 Summary of Lost Capability Due to Loss of QuikSCAT Was the loss of QuikSCAT expected to impact forecasts? Can such an impact be quantified? (Is there a bias trend in numerical wave forecasts, for example?) Oceansat-2 coverage would be great, but operational decisions can t be based on it (yet)

24 Summary of Lost Capability Due to Loss of QuikSCAT Ability to detect storm-force winds with satellite ocean vector wind data Ability to fully detect area impacted by gale-force winds in strongest events Ability to compare the model wind field with observations over a large spatial area Decreas ed forecaster confidence for severity, coverage, and timing of most extreme events